The advent of the hydrostatic transmission has dictated the need for an operator control system which will selectively actuate a control valve of the transmission into its various operative positions. In addition, the operator must closely control the speed of the engine which drives the pump of the hydrostatic transmission, simultaneously with actuation of the control valve. It is desirable to construct and arrange such a control system in a compact and non-complex manner, including the use of a minimum number of movable components in the linkage systems therefor.
In addition, it is further desirable to employ a foot pedal or the like which is adapted to be rocked in opposite directions to place the transmission in its forward or reverse modes of operation and simultaneously effect a unidirectional movement of a throttle control for the engine. U.S. Pat. No. 3,952,512, assigned to the assignee of this application, discloses a control system of this type wherein a bidirectional control valve of a hydrostatic transmission and a unidirectional throttle control for an engine are operated simultaneously by a common foot pedal.